As one of noises generated in a pneumatic tire, there is cavity resonance sound which is generated due to the vibration of the air filled in the tire. When the tire is running on a road surface, the tread portion is vibrated due to the roughness of the road surface. The vibration of the tread portion causes the air in the tire to vibrate, so that the cavity resonance sound is generated. It is known that the frequency of the cavity resonance sound of a pneumatic tire is approximately 250 Hz.
Conventionally, as methods of reducing the cavity resonance sound in a pneumatic tire, the following ones have been proposed. In the methods, one or more noise absorbing members formed of a porous material are attached continuously or with intervals to the tire inner peripheral surface of a tread portion so that cavity resonance sound is absorbed by the noise absorbing members (for example, see Patent Documents 1 and 2).
In the case of the tire having noise absorbing members attached to the tire inner peripheral surface thereof as described above, when the tire comes to the end of life due to wear or the like, the noise absorbing members are discarded together with the tire having come to the end of life. However, there is another method of attaching noise absorbing members, that noise absorbing members are bonded to an elastic band in advance and then attached indirectly to the tire inner peripheral surface by using the elastic band. According to the method, even when the tire comes to the end of life, the noise absorbing members are removed together with the elastic band so as to be reused in another new tire. For this reason, this method is beneficial for resource conservation.
However, in a case where the noise absorbing members are indirectly attached with the elastic band, the noise absorbing members move relatively in the tire circumferential direction when the tire rotates. For this reason, when the tire runs over a nail on the road and then continues to run, the tip of the nail tears the noise absorbing members moving relative to the tire inner peripheral surface. This leads to a problem in which it is impossible to reuse the noise absorbing members.                Patent Document 1: Japanese patent application Kokai publication No. Sho62-216803        Patent Document 2: Japanese patent application Kokai publication No. 2003-252003        